Broken Crankcase, is this common?

[rc46joe]

I have an 03 yz250f with a broken right side engine case. It is broken at the inside of the kickstarter shaft on the top of the case. It loos like the kickstart gear pushed something through the case. Is this a common problem? and when I put it back together how can stop it from happening again. I have not taken it apart yet but will in the next two days. I did search this and found nothing. Thanks for any info you can offer, Joe.

[Toby_S]

You need to figure out what got pushed through the case. My brother had a transmission gear tooth pushed through his case. His mechanic replaced the gear and fixed the case with JB weld, and that worked fine. If you do JB weld, you have to prep the surface really well - maybe contact cleaner followed by acetone.

-Toby

[XtremeDuners]

I have an 03 yz250f with a broken right side engine case. It is broken at the inside of the kickstarter shaft on the top of the case. It loos like the kickstart gear pushed something through the case. Is this a common problem? and when I put it back together how can stop it from happening again. I have not taken it apart yet but will in the next two days. I did search this and found nothing. Thanks for any info you can offer, Joe.

I had this same thing happen with a 03 450F, sounds to be in the same spot. It was about 25 degrees outside and that probably had something to do with it, I was kicking the snot out of it because it was running way lean. Of course this was in my younger dumber days of doing things.

Are you cranking on the kick starter? 4 strokes don't have to be kicked hard, just long. Anyways, good luck.?

[rc46joe]

I have an 03 yz250f with a broken right side engine case. It is broken at the inside of the kickstarter shaft on the top of the case. It loos like the kickstart gear pushed something through the case. Is this a common problem? and when I put it back together how can stop it from happening again. I have not taken it apart yet but will in the next two days. I did search this and found nothing. Thanks for any info you can offer, Joe.

The same thing happened to my 03 250f. So I guess so??? Got a case half from a wr and pulled the motor to fix it. A whole bunch YZ and WRs are interchangeable. I think I payed less than $100 for the case half.
To start mine I would turn on fuel, choke it, stroke the kicker slowly three times, get the piston to the top of the compression stroke and kick it once more and it fired right up. Hot or cold. Check valves, maybe do a jet kit as well.